The present invention relates to a test specimen grip assembly and, more particularly, to a load train grip assembly for holding a metallurgical specimen in a test apparatus for performing tensile, creep/stress or like analyses.
A typical metallurgical test specimen is disclosed, for example, in U.S. Pat. No. 3,107,522, and includes a main body generally of linear or axial extent with frusto-conical end portions to facilitate gripping of the same in a tension testing machine. The end portions are gripped in respective cylindrical holders by work holding jaws formed by a pair of pins inserted through respective bores in the holder, the pins being rotatable in their bores to facilitate self-centering or self-alignment of the specimen in the axial direction as tensile force is applied. In U.S. Pat. No. 3,107,524 a hemispherical seat in a cup holder receives a split hemispherical bit that forms a self-aligning jaw.
Tension or like testing machines are, of course, known in which tensile force is applied to a specimen under ambient, heated, or cooled conditions to effect metallurgical or like analyses of the specimen.
Although prior gripping devices provide for some self-alignment or self-centering of a specimen during tensile or like testing thereof, at the conclusion of such testing it is often-times difficult and time consuming to separate the respective parts of such prior gripping devices and the specimen gripped thereby because of inelastic shape changes of those parts. Also, in many instances some of the grip assembly parts must be replaced before the device can be reused again or after a few times, which greatly adds to the overall cost of the device and restricts its usefulness.